This invention relates to a closure assembly for a container, particularly of the type disposed under the hood of automotive vehicles. The closure assembly comprises a filler nipple (which is an integral part of the container), a plug unit and a pivotal actuating lever operating the plug unit. The plug unit may be locked in the filler nipple by means of a component of the plug unit releasably extending into a depresson provided on the inner wall face of the filler nipple. The plug unit includes a plug housing and a sealing ring accommodated in an annular clearance defined by the plug housing. The sealing ring is made of a flexible material and may be radially expanded against the inner wall of the filler nipple by spreader fingers and is, by means of its cross-sectional deformation occurring during such expansion, pressed against the housing walls defining the annular clearance.
A closure assembly of the above-outlined type is known and is described, for example, in European Pat. No. 27,970.
Upon closing the plug unit of the known closure assembly, the sealing ring is, by means of its radial expansion, form-fittingly pressed into an annular groove formed in the inner wall of the filler nipple. The sealing ring performs both a sealing function and a holding function. Under extreme stresses, for example, in case of an accident, the holding force of the known construction may prove to be insufficient. Further, the aeration or air removal involved in the opening of the plug unit presents problems in containers which are maintained under or above atmospheric pressure.